DE-A-3,723,555 proposes a method for the manufacture of a dental prosthesis wherein contour lines are projected by an optical groove grating onto a ground or polished stump and produce moire contours, with the optical groove grating being photographed by a camera. At least three different contour line patterns are produced, and from the three moire images obtained, it is possible for each camera image point or pixel to calculate the vertical coordinates on the stump and therefore the position for each point of the stump surface.
The above proposed method is complicated and requires complicated and expensive equipment and it is also not clear as to how, in practice, the method can be carried out on a stump in the mouth of a patient.